Explictly set WPA_SUPPLICANT_VERSION := VER_0_8_X for the generic devices

Since 558477c0b2a5a7db679c1ad7551d43e6364d1df2 in
external/wpa_supplicant_8 we don't have WPA_SUPPLICANT_VERSION default
to VER_0_8_X.
This fixes the SDK build.

Change-Id: Ib7a8e10705dc6b987b60b1308405e89eaa2a47c9